• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.631-637
• /
• 2005

This paper presents a stiffness analysis method for a low-DOF parallel manipulator, which takes into account of elastic deformations of joints and links. A low-DOF parallel manipulator is defined as a spatial parallel manipulator which has less than six degrees of freedom. Differently from the case of a 6-DOF parallel manipulator, the serial chains in a low-DOF parallel manipulator are subject to constraint forces as well as actuation forces. The reaction forces due to actuations and constraints in each limb can be determined by making use of the theory of reciprocal screws. It is shown that the stiffness model of an F-DOF parallel manipulator consists of F springs related to the reciprocal screws of actuations and 6-F springs related to the reciprocal screws of constraints, which connect the moving platform to the fixed base in parallel. The $6{times}6$ stiffness matrix is derived, which is the sum of the stiffness matrices of actuations and constraints. The six spring constants can be precisely determined by modeling the compliance of joints and links in a serial chain as follows; the link can be considered as an Euler beam and the stiffness matrix of rotational or prismatic joint can be modeled as a $6{times}6$ diagonal matrix, where one diagonal element about the rotation axis or along the sliding direction is zero. By summing the elastic deformations in joints and links, the compliance matrix of a serial chain is obtained. Finally, applying the reciprocal screws to the compliance matrix of a serial chain, the compliance values of springs can be determined. As an example of explaining the procedure, the stiffness of the Tricept parallel manipulator has been analyzed.

• The International Journal of Costume Culture
• /
• v.3 no.3
• /
• pp.212-222
• /
• 2000

This study intends to observe how the essential elements of art have changed Human's sense of beauty extending over the whole lives as well as fashion through the investigation of Light and Rays which have played a important role in giving birthe to the new trend of art within the upheaval age of various cultures. The peculiarities of which Futurism of Italy and Rayonism of Russia including Impressionism have a great role in giving birth to a new trend of art by means of the development of science technology are like these. Impressionists looked for the origin of the subtle harmony in nature within changes of sun-rays. The special feature of Impressionism paintings was to express the line of vision diversely according to changes of light rather than to focus on the line of vision with clear outlines. Henceforth, Neo-Impressionism which developed Impressionism more systematically leaded changes of Light and Rays more systematically and scientifically and maintained Divisionnisme techniques which extends to lead towards color and light through dividing and juxtaposing color. In the early 20th century Futurists tried to express dynamism through the interpenetration of light and revive color and light through the division techniques of color and persist an artificial light like eletricity rather than a natural light. Rayonism of Russia which was ifluenced from Impressionism and Futurism maintained intersection of reflecting rays which emerges from an object of things more deeply. This pursuit of light and rays also light and rays also appears as it is in modern fashion. First, it is the fashion which applied sun-rays persisted by Impressionists and expressed colors which show differently according to direction of light. Second, it is the fashion design which re-analyzed what Futurists expressed artificial light and rays. Third, it is the design which expressed Divisionnisme theory persisted by Impressionists and Futurists into fashion as it is and was made of being divided the form of glittering light into small dots. Fourth, it is the fashion design which applied Rayonists'work which applied intersection of reflected rays. Like this, it is aproved that the pursuit of light and rays expresses as it is in modern fashion of the 21st.

• Convergence Security Journal
• /
• v.15 no.3_2
• /
• pp.11-19
• /
• 2015

This paper, so far to analyze the research trends in the issue that has been discussed for the introduction of private investigation institutions, by projecting its suggestion, want the investigation purpose of presenting the desirable introduction direction. The analyzed issue was extracted for existing research material on the introduction of private investigation institutions. Investigators pointed out issue is the name, business scope, corporate, qualification system (eligibility criteria and test), education, association establishment, regulatory agencies, has been included in the eight categories such as legislation form. For the name, I think there is a need to unify under the name "detective". For the scope of work, the amendment is difficult law, place an overview of the general business rules, more specific and detailed investigation business content, to discipline through the ordinance it is possible to be rational. Private investigation institutions, I think the need for limited operations of the corporation. For education, the new education and re-education on a regular basis I do for the private investigation workers. You must be one of the National Police Agency to the management authority. Legislative form, not to be defined by its own law, the revision of the security law, but that is to complement the provisions for private sector research system is effective.

• Proceeding of KASS Symposium
• /
• 2008.05a
• /
• pp.101-106
• /
• 2008

This paper describes a comparative study of genetic algorithm and mathematical programming technique applied in the design optimization of geodesic dome. In particular, the genetic algorithm adopted in this study uses the so-called re-birthing technique together with the standard GA operations such as fitness, selection, crossover and mutation to accelerate the searching process. The finite difference method is used to calculate the design sensitivity required in mathematical programming techniques and three different techniques such as sequential linear programming (SLP), sequential quadratic programming(SQP) and modified feasible direction method(MFDM) are consistently used in the design optimization of geodesic dome. The optimum member sizes of geodesic dome against several external loads is evaluated by the codes $ISADO-GA{\alpha}$ and ISADO-OPT. From a numerical example, we found that both optimization techniques such as GA and mathematical programming technique are very effective to calculate the optimum member sizes of three dimensional discrete structures and it can provide a very useful information on the existing structural system and it also has a great potential to produce new structural system for large spatial structures.

• Journal of the Korean Geotechnical Society
• /
• v.18 no.2
• /
• pp.65-74
• /
• 2002

The measurement of in-situ stress is essential to estimate the ground displacement and the stress distribution of a tunnel and an underground structure. In this study, the in-situ stress distribution of the Southern Korean peninsula was re-evaluated by the new 380 in-situ data which were determined by overcoring and hydrofracturing methods, and the three-din erosional numerical analysis of tunnelling was performed. The results of in-situ stress distribution show that the distribution of horizontal stress tends to be more irregular in metamorphosed(gneiss) and granite areas than in sedimentary and volcanic areas. The ratio of horizontal to vertical stresses(K-value) in volcanic area is less than 1 below the depth of 150m. The direction and magnitude of three dimensional in-situ stresses were shown simultaneously in a figure for the first time in Korea. The three-dimensional numerical analysis of tunnelling indicates that the orientation and magnitude of displacement around a tunnel are controlled mainly by the difference between the maximum and minimum horizontal stresses.

• 유체기계공업학회:학술대회논문집
• /
• 2006.08a
• /
• pp.187-190
• /
• 2006

In the present study, effects of tree-stream turbulence and surface trip wire on the flow past a sphere at $Re\;=\;0.4\;{\times}\;10^5\;{\sim}\;2.8\;{\times}\;10^5$ are investigated through wind tunnel experiments. Various types of grids are installed upstream of the sphere in order to change the tree-stream turbulence intensity. In the case of surface trip wire, 0.5mm and 2mm trip wires are attached from $20^{\circ}\;{\sim}\;90^{\circ}$ at $10^{\circ}$ interval along the streamwise direction. To investigate the flow around a sphere, drag measurement using a load cell, surface-pressure measurement, surface visualization using oil-flow pattern and near-wall velocity measurement using an I-type hot-wire probe are conducted. In the variation of free-stream turbulence, the critical Reynolds number decreases and drag crisis occurs earlier with increasing turbulence intensity. With increasing Reynolds number, the laminar separation point moves downstream, but the reattachment point after laminar separation and the main separation point are fixed, resulting in constant drag coefficient at each free-stream turbulence intensity. At the supercritical regime, as Reynolds number is further increased, the separation bubble is regressed but the reattachment and the main separation points are fixed. In the case of surface trip wire directly disturbing the boundary layer flow, the critical Reynolds number decreases further with trip wire located more downstream. However, the drag coefficient after drag crisis remains constant irrespective of the trip location.

• Journal of the Society of Disaster Information
• /
• v.5 no.2
• /
• pp.50-73
• /
• 2009

This paper is about the establishment of "Initial Response System." Initial response system is most important and should be treated urgently among all preparations for chemical terrorism. The objects of Initial response system are to protect civilians and the first responder who are exposed directly to chemical terrorism. Therefore, this paper suggests two main issues about Initial response system. One is to prepare immediate and exact information service system which assures the safety and survival of exposed people. The other is to build Scene Response System integrated with Command-Control Procedure for early finished situation. Compared to United States, overcoming the Chemical Terrorism requires to improve the contents of two categories: Counter Citizen Response part and Initial Scene Response part. For Counter citizen response part' s sake, the web-sites of Response leader agencies for searching information about chemical terrorism should be modified specifically. These web-sites have to be re-organized in detail. The existing Information service system which has been vaguely informed as "CBRNE Accident" needs to be divided as "CBRNE Accident" and "WMD terrorism." Further, each of them should be specialized in "Chemical', "Biological", and "Radiological" categories. There is a need to rearrange current Emergency Instruction for civilians against chemical terrorism in feasible way. At the same time, it should be applied consistently to all organizations through agreement between experts and related-organizations. For Initial Scene Response part's sake, "Initial scene response procedure (SOP)" and "Operational conception" should be produced through Simulated Exercises and workshops of all organizations related with initial response. These organizations have to cooperate with Ministry of Environment which is the main leader Agency as the center. Next, there is a need to develop a technology and Scene Response Equipments, and to standardize the response equipments which consider the capability of First Responders for chemical terrorism. Especially, improving capability of equipments is required to overcome the vulnerability of Scene Response Equipments.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.29 no.5
• /
• pp.268-273
• /
• 2016

In this study, we observed current-voltage characteristics of the MIM (metal-insulator-metal) structure. The $WO_x$ material was used between metal electrodes as the oxide insulator. The structure of the $Al/WO_x/TiN$ shows bipolar resistive switching and the operating direction of the resistive switching is clockwise, which means set at negative voltage and reset at positive voltage. The set process from HRS (high resistance state) to LRS (low resistance state) occurred at -2.6V. The reset process from LRS to HRS occurred at 2.78V. The on/off current ratio was about 10 and resistive switching was performed for 5 cycles in the endurance characteristics. With consecutive switching cycles, the stable $V_{set}$ and $V_{reset}$ were observed. The electrical transport mechanism of the device was based on the migration of oxygen ions and the current-voltage curve is following (Ohm's Law ${\rightarrow}$ Trap-Controlled Space Charge Limited Current ${\rightarrow}$ Ohm's Law) process in the positive voltage region.

• Korean Medical Education Review
• /
• v.22 no.3
• /
• pp.173-188
• /
• 2020

Medical humanities education (MHE) is as essential as basic medical sciences and clinical medicine education. Despite the importance of MHE, MHE curriculum development (CD) has proven to be challenging. This critical review examines the MHE CD at one medical school. The critical review methodology was developed based on Kern's six step CD model to systematically examine the CD of "Doctoring and Medical Humanities (DMH)" at the Yonsei University College of Medicine. Five review questions were developed related to (1) necessity, (2) direction and purpose, (3) design, (4) operation, and (5) evaluation of CD based on Kern's model. The review showed that the process of DMH CD mapped to components of Kern's model. The DMH curriculum content selected was closely related to medical practice and aimed to combine the acquisition of understanding and skills by designing a student-participatory curriculum based on clinical cases. Assessment methods that emphasized students' reflections were actively introduced in the evaluation section. Since the regular committee for DMH continued the work of the special ad hoc committees for DMH CD, the CD was effectively completed. However, the planning and evaluation functions and responsibilities of the DMH committee need to be strengthened. Despite the apparent limitations, the fact that students showed a high satisfaction rate and preferred small group discussions based on clinical cases has significant implications in the instructional design of MHE, where changes in self-awareness and attitude are more important than the acquisition of information. It is necessary to systematically review and study students' reflection results produced by the changed assessment methods and to develop assessment indicators for MHE that reflect the achievements of the MHE competencies of students.

• Korea Multimedia Society
• /
• v.14 no.4
• /
• pp.88-98
• /
• 2010

It is now the era of ubiquitous which is highly integrated on the convergence technologies with not only ICT bul also BT, CT, NT and ST. Through this convergence technology, the understanding on visualization of 3D virtual reality which make more human's 5 feelings activate beyond the wall of time and space is recently very important. We search the visualization technology of 3D virtual reality and estimate the future development, and give the perspectives. Since the visualization technology of virtual reality is strongly depended on 3D computer graphics representations, 3D image visualization technology being able to get immersion has been possible. The new paradym on computer interactions is implemented by making images augment on the base of the PC and display equipments. The studies is established on the direction of more intensity on humanity. And also, these technologies will be able to achieve actively the implementations for ubiquitous society dueing to get the high-technology on the superhighway networks.